|Female cats are unusual in that their heats are influenced by seasonal changes in the amount of daylight. Cats usually 'cycle' and are bred between January and September. Starting around January, a female cat will keep coming back into heat every 7-10 days until she is bred or the amount of daylight decreases (usually around October).
As you are very aware, a cat in heat is very vocal, calling and calling for a male cat. She will roll and roll on the ground and constantly rub against furniture or your leg. She will assume a breeding posture with her head and front legs near the ground and the rump area held high. You may notice her urinating frequently.
There is a cure. Spaying your cat will eliminate all these signs of being in heat and also eliminate the risk of certain diseases including ovarian cancers and infections of the uterus.